Studying the neuroanatomical substrates of stress, suicide and depression in human brain is the central theme of this project. While these are also major foci of this entire Program Project application, this project specifically emphasizes postmortem human brain in an effort to understand the fundamental anatomy of stress-related circuits in man, and the possible changes in gene expression within these circuits which may accompany suicide and depression; in addition, however, this project includes some pre-clinical studies in the rodent specifically focused on the interface between stress circuits and the sites of action of antidepressant drugs, as these studies will help us interpret the human findings. Therefore, this project comprises 3 Specific Aims. The first Specific Aim involves the study of serotonergic (5HT) and nor-adrenergic (NA) systems as they respond to stress and antidepressants in rodent models. These paradigms will allow us to establish a clearer view of the functional links between the stress axis and monoamine systems, thereby clarifying the impact of monoamine-altering compounds on depression and on the endocrine disturbances associated with it. The second Specific Aim directly analyzes postmortem human brain from suicide victims, suicide victims also having a documented history of affective disease, and controls. The same circuits and systems laid out in the rodent will now be analyzed inhuman brain (prefrontal cortex, limbic circuits associated with the stress axis, 5HT and NA nuclei and their receptors). The third Specific Aim is designed to allow the three-dimensional (3D) analysis of individual human brain nuclei at cellular resolution using mRNA levels. This method will substantially increase the power and value of human postmortem studies by combining the regulatory information found in mRNA levels with anatomical precision and with high resolution statistical tools. In sum, at the end of the requested 5 years of this proposal we expect that we will have made very substantial gains in appreciating the circuitry of the stress axis in rodent and man, and begun to establish the relationship between the stress axis and affective disease at the level of biochemically specific brain nuclei and structures.